SEW-Eurodrive MOVIMOT flexible MMF3 C/DBC Series - Page 300

10
Project planning
Selecting the braking resistor
Operating Instructions – MOVIMOT
®
flexible
300
10.8.4 Calculation example
Given
• Peak braking power: 1kW
• Average braking power: 0.4kW
• Braking time: 7s
• Cycle duration: 28s
Required
• Braking resistor BW...
Calculation
1. Determining the cyclic duration factor
• Cyclic duration factor cdf = braking time/cycle duration
• Cyclic duration factor cdf = (7 s/28 s) × 100% = 25%
When selecting the braking resistor, observe the assignment of inverter and bra-
king resistor, see chapter "Technical data and dimension sheers" > "Braking resist-
ors".
2. Determine the overload capacity
Determining the overload factor, e.g. for a flatpack resistor at a cyclic duration
factor cdf of 25% from the respective diagram.
• Overload factor OF = 3.0
3. Calculating the braking power at 100% cdf
• Braking power 100% cdf = average braking power/overload factor
• Braking power 100% ED = 0.4W/3.0 = 0.133kW
• The braking power of the braking resistor at 100% cdf must be ≥0,133kW.
4. Selecting the braking resistor
• For MOVIMOT
®
 flexible, the minimum permitted braking resistance value =
100Ω, see chapter "Technical data and dimension sheets".
• Selected braking resistor: BW100-005/K1.5
• Resistance value R
BW
= 100 Ω
• Peak braking power: 1.8kW
• Current-carrying capacity at 100% cdf: 0.2kW
29129451/EN – 12/2019